C.J. Far question and I think I am guilty of throwing out words that are causing confusion as it pertains to our goal of growing fig fruit in colder climates, e.g. "Heat Units." While the definition of a "Heat Unit" is a unit of measurement for work, I think you and others more appropriately have and continue to discuss "heat trapping" as it relates to ripening fig fruit.

The short answer to your second question of whether or not you need to worry about baking your roots on your large expanse of exposed rock is yes. I have included another thread for your consideration.

As an aside if you can insulate and/or protect your fig pots on that large expanse of rock my guess is you will experience great results. The rock will store the solar energy and release it at night thus moderating night time lows by using thermal mass. Generally this is what is achieved when those in colder climates plant figs trees alone the southern wall of their homes.

Sorry if I created any confusion!
Vinnie

Here is a link that might be useful: Heat Stress

C.J.
this is my situation, i live in cold climate near chicago and have fig put containers on my 4 to 6 inch thick cement patio 20x30 ft.This year i moved them to the rock area which also get full sun and have my smaller pots on patio. I always have had the plants placed like this and sure they wilt a little and you have to stay on top of the watering when they need it , in my case the heat of summer which gets into the high 80s and on ocassion the 90s i have to water what seems like every other day.
My fig trees love it and produce well for my area. Im currently looking for large black containers for a few types i have that i want to along with full sun give more bottom heat to roots and soil as these are not suppose to do well in my climate but i experiment.
Best Season
Martin

Vinnie,

That was a helpful thread on heat stress. Do you think an isolation barrier such as a pad of Styrofoam insulation between the rock and the bottom of the pot would enough protection, or do I need insulation for the entire pot?

Martin,

Your situation IS very similar to mine and the information that you provided is very encouraging. Normally, my summers are pretty mild, but last summer was a killer with endless days of temps in the high 80's and 90's. We seem to be going back to the ice age in the Northeast this year.

Unfortunately, the south side of my house is completely shaded and the further I get my the house, the greater my problems with varmints (raccoons, squirrel, bears, neighbors. Just kidding about the neighbors)

I guess we learn by doing.

C.J.

I like the "heat unit" term as applied to fig ripening. Figs need a certain amount of heat over a period of time in order to trigger the ripening process and produce sugar. I think of "heat units" as very analogous to the "chill hours" term. Fruit trees need a certain number of hours below 45 degrees before they will produce flowers. Figs need a certain amount of heat to fully ripen figs.

Dan

C.J. in my opinion you don't need to worry about creating a buffer between the rock and your potted plants. My primary concern would be placing young trees, in small pots, in the sun, during high tempertures, on stone or concrete. In my opinion that is a recipe to lose a prized plant.

As Martin indicated you do need to be alert when the weather heats up as your potted plants may get stessed.

I may be in the minority here, but if you're worried about your container fig plant getting heat stressed on the rock expanse, I would go with a larger pot/container. The larger the pot the easier it is to maintain (my opinion again).

Eventually you will get to a maximum pot size and will have to root prune your plants to keep them viable. Hopefully you will grow large productive fig trees in containers that Martin (and others) have achieved.

Below is a really good thread on root pruning and container figs.

Here is a link that might be useful: Part of Fig don't care about to much-How about you

The heat units ,as applied to figs is,a certain amount of heat needed,by the fig trees,to get the fruits ripe.
It counts ,to figs,only from the moment the fruits ,are in the stagnant stage,till they get ripe.
It can be attained in a couple of weeks,or in 2 month,but if not attained,those fruits will never get ripe.
The plants and fruits grow very well,now ,here where we have a very cold rainy period(60F,for weeks),but if it gets to the stagnant stage and we do not get hot Sommer days,then they will never ripe.
That is Why:Ideal climate for ,comercial fig,growing ,is a rare luxury,while ,almost satisfactory growing climate ,can be easily found.
Of course with extra help,and intervention,from Grower,they succed,in such climates.
H

Okay, what is it exactly that makes a fig ripen? Is it the amount of heat to the roots or to the entire plant. I saw an interesting picture on stevec's "Fig Orchard" site at http://www.pbase.com/scascio/image/80271483. His pots are half-buried in a raised bed. Then what appears to be later in the season when, presumably, the temperatures are significantly higher, the entire bed is covered with what looks like a thick layer of hay. I imagine the hay serves 2 purposes; it keeps down the weeds and it reduces the amount of heat that reaches the roots.

And what does stagnant" mean when talking about a fig. Does that term refer to the little bump that becomes the fig, or a fig that has developed but does not ripen?

I think I understand that cold temperatures cause stagnation, but is there a specific point in the development of the fig when the fruit will not ripen further because the development has been stunted by cold weather? Can the stagnation be broken or reversed?

As Herman says, we have had weeks of gloomy, rainy, 60 degree days here in the northeast. I have some figs forming but they are nothing like that other pics I've seen on this forum. Even my "pet rock" (the front yard) is cold right now. Should I start worrying? Break out the heat lamp? Pray?

Inquiring minds want to know.

Jenia here is example of my trees and were they are this season (click thumbnail to enlarge) last season nothing was on rocks but due to more plants i have some on rocks for heat and rest on patio.We had much rain this seasonand last couple days as you can see.
Everyone has different methods of placing and growing figs trees depending on where they live, if i was in Florida(maybe 1 Day) i dont think i could get away with potted fig plants on cement patio in full sun for the growing season but not sure because i dont live there and have not tried it. I just do my plants this way because i live in cool climate , in early spring im wheeling the plants in an out of garage to get a head start but nights get below freezing and i have to put them back in garage.
Spring time here is usually cool just like this year but this year cooler than normal, summers are nice and warm but September can be a funnny month with the temps especially at night. So by my plants sitting on cement or rocks helps keep them warm in early spring , probably much warmer in summer as i have to water them much more and in early fall warm again similar to spring as nights get cooler.
This works for me in my area but everyone adjusts to there area in the way they grow them. If your season is similar you can try placing pots directly on rocks and see what happens just watch when they need watering.
When you find out what works for you my only advice would be stick to it and also try to grow fig plants that are better suited for your climate as for me do not pay attention to my type as i do not follow that rule , i like the challenge to see what i can grow.
Best Season To You
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I Can't comment about Steven's Technique,but I can say,that Dieseler way,of Getting his figs to grow faster,is very smart.
The fruits starts as small embri\yos,and they grow every day,to about the size of a 25 cents coin.
At this point they do not grow anymore for a period of about 40 days.This period is the stagnant period.
Here in New Jersey it Happens in between,1st of July,and 10th of August.This is the stagnation period.
Then suddenly on August 10 the fig double its size overnight and in another 5 days,on 15th of August,it is ripe.
This Period (July 1st-Aug 10),is critical for the weather to be hot,and so the stagnating fruits accumulate heat units.
If it is not hot enough,the fruits will not ripe,on 15th of August,but much later in September or Octomber,when enough heat units are gained,Hopefully.
If it continue to be cold ,and rainy,then they will never ripe.
The Succesfull scenario I was explaining above is only possible if the tree is growing,in full sun.
In our climate planting it in partial shade,is making sure the tree will have a handicap,from the start.
Yet fig trees tolerate shade very well,in hotter climates,like Central Ca,and they also get ripe just as well,in that climate.
Stay well
H

Herman,

That is some amazing information about the stagnation/maturation periods of the fig fruit. This is the first time I have ever heard this.

I am moving everything but the LUS Purple and a couple of others out to the rocks in about 30 minutes. The remainder is in my very small greehouse until the weather gets warmer. The high here yesterday was 64. I've never seen a June like this.

C.J.

Jenia: I missed to point out that this scenario,and timing apply to the first fruits group,that appear on the tree.
Later on figs continue to form,but those will follow the same path,yet they will ripe later,to the end of August and September.
And all explanation is true only for main crop,the fruits that appear on new growth.
These are the fruits I was interested in,and studied the cycle,and not the Breba crop.
I am not very experienced with breba figs,nor do I know all the secrets of high breba production.
That is Why I have Desert King ,5 yrs old,and the most I had was 4 ripe fruits in a year.
I am sure there is a better way to make it fruit.
H